Let flex handle the input stack (issue 563560043 by address@hidden)

[jonas . hahnfeld]

Reviewers: ,


https://codereview.appspot.com/563560043/diff/567260043/aclocal.m4
File aclocal.m4 (right):

https://codereview.appspot.com/563560043/diff/567260043/aclocal.m4#newcode556
aclocal.m4:556: # check for yyFlexLexer.yypop_buffer_state () since flex
2.5.29
Random thought: Do we want to check for features introduced in 2003 or
can we just assume that we never come across ancient versions that don't
support this?

https://codereview.appspot.com/563560043/diff/567260043/lily/lexer.ll
File lily/lexer.ll (right):

https://codereview.appspot.com/563560043/diff/567260043/lily/lexer.ll#newcode753
lily/lexer.ll:753: <maininput>{ANY_CHAR} {
David, you added this code in commit 6b0ff05318 ("Make lexer more robust
against unexpected EOF"). Do you have an idea what I have to do to end
up in this code path? I didn't manage to trigger so far :-( I think that
the new code is equivalent to the old one, but would prefer to check on
an example.

Description:
Let flex handle the input stack

This requires at least flex 2.5.29 released in 2003.

Prior cleanups:
1) Use Includable_lexer::new_input in Lily_lexer

Only Includable_lexer::new_input (const string &, Sources *) is virtual,
the method with type (const string &, const string &, Sources *) should
not be declared.

2) Deduplicate code from Includable_lexer::new_input

Please review this at https://codereview.appspot.com/563560043/

Affected files (+41, -87 lines):
  M aclocal.m4
  M config.hh.in
  M lily/includable-lexer.cc
  M lily/include/includable-lexer.hh
  M lily/include/lily-lexer.hh
  M lily/lexer.ll
  M lily/lily-lexer.cc